Food slicing machines

ABSTRACT

A slicing machine has a base which supports an inclined rotary knife driven by a motor and covered by a removable knife guard. A carriage is supported for reciprocation adjacent the knife and an adjustable gage plate, and includes a removable inclined tray member for supporting the articles to be sliced. A first interlock system prevents removal of the tray member until the gage plate is set at zero or flush with the knife, and a second interlock system prevents operation of the motor when the knife guard is removed for cleaning. A third interlock system assures that the motor will not operate when the knife guard is being reassembled in the event the main motor control switch was inadvertently actuated when the knife guard was removed.

United States Patent Pratley 1541 FOOD SLICING MACHINES [72] Inventor: Clifford Pratley, London, England [73] Assignee: The Hobart Manufacturing Company, Troy, Ohio [22] Filed: Oct. 5, 1970 [21] Appl. No.: 78,091

7/1951 Lundell ..l46/l02 H 1 Dec.5, 1972 Primary Examiner-Willie G. Abercrombie Attorney-Marechal, Biebel, French and Bugg [57] ABSTRACT A slicing machine has a base which supports an inclined rotary knife driven by a motor and covered by a removable knife guard. A carriage is supported for reciprocation adjacent the knife and an adjustable gage plate, and includes a removable inclined tray member for supporting the articles to be sliced. A first interlock system prevents removal of the tray member until the gage plate is set at zero or flush with the knife, and a second interlock system prevents operation of the motor when the knife guard is removed for cleaning. A. third interlock system assures that the motor will not operate when the knife guard is being reassembled in the event the main motor control switch was inadvertently actuated when the knife guard was removed.

7 Claims, 11 Drawing Figures PA'IENTEOIIEI: 5:912

SHEET 1 [IF 2 FIG-I FIG-3 INVENTOR A TTORNE' Y5 PATENTED DEC 5 I972 SHEET 2 OF 2 FOOD SLICING MACHINES BACKGROUND OF THE INVENTION In a food slicing machine as disclosed in U.S. Pat.

No. 3,051,207 and in British Pat. No. 955,343, which issued to the assignee of the present invention, it is common to mount the inclined food support tray on the reciprocating carriage so that it can be conveniently removed to facilitate cleaning of the tray aswell as cleaning of the adjustable gage plate and the knife. It is also common to provide for removing the guard plate which partially covers the knife to simplify cleaning of the knife.

It has been found desirable to prevent removal of the carriage tray member unless the adjustable gage plate is positioned at its zero setting or flush with the cutting edge of the knife. This assures that the exposed portion of the sharp cutting edge ofthe knife is guarded or protected when the tray member is removed and thereby reduces the possibility of the operators hand inadvertently slipping and engaging the sharp cutting edge of the knife. It has also been found desirable to prevent operation of the drive motor for the knife when the guard plate covering the knife is removed for cleaning purposes. Furthermore, when the knife guard plate is removed, it is desirable to assure that the knife will not begin rotating while the guard plate is being replaced in case the main control switch for the motor was inadvertently actuated while the knife guard is removed.

SUMMARY OF THE INVENTION the knife when the knife guard is removed or is being reassembled.

In accordance with a preferred embodiment of the invention, the carriage tray is secured to the carriage support arm by a mechanism which can be operated only when the carriage is in its forward position and the gage plate is at its zero setting. The knife guard is mounted on an elongated rod which extends through a tubular drive shaft for the knife and is retained by a lock pin extending from a knob. When the lock pin properly engages the support rod of the knife guard to lock the guard in place, a normally open switch in series with the knife drive motor is closed. When the knife guard is removed, the switch remains open so that the motor cannot be energized.

The control circuit for the motor includes a main motor control switch and also a holding circuit consisting of a relay which is actuated by another interlock switch adapted to be momentarily closed when the main control switch is closed. This control system assures that the motor cannot be energized until after the knife guard is replaced and secured and then the main control switch is actuated.

Other features and advantages of the invention will be apparent from the following description, the accompartying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a food slicing machine constructed in accordance with the invention;

FIG. 2 is a fragmentary perspective view of the machine shown in FIG. 1 and with some of the components exploded and with other components shown in phantom to show internal construction;

FIG. 3 is a fragmentary section taken generally on the line 33 of FIG. 1;

FIG. 4 is a fragmentary section taken generally on the line 4-4 of FIG. 3;

FIG. 5 is a fragmentary section taken generally on the line 55 of FIG. 8; I

FIG. 6 is another fragmentary section taken generally on the line 6-6 of FIG. 8;

FIG. 7 is a schematic electrical wiring diagram for the machine;

. FIG; 8 is a fragmentary section taken generally on the line '88 of FIG. 10; v 3

FIG. 9 is a fragmentary perspective view of a portion of the interlock mechanism shown in FIG. 2;

I FIG. 10 is a fragmentary elevational view of the machine and with portions broken away to show internal construction; and

FIG. 11 is a fragmentary. plan view of the control mechanism for operating the knife drive motor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The slicing machine shown in FIG. 1 generally includes a housing 15 forming a base with an upwardly projecting hollow portion 16 at one corner, an elongated upwardly projecting hollow portion 18 along one side and a horizontal platform surface 20. Referring to FIG. 3, an electric motor 25 is mounted within the housing portion 16 and includes an output shaft on which is mounted a worm gear 26. An inclined tubular shaft 28 is rotatably supported within the housing portion 16 by a set of anti-friction bearings 29 and has an upper end portion 31 having external threads. A gear 33 is mounted on the lower end portion of the tubular shaft 28 and engages the worm gear 26 so that the shaft 28 is driven by the motor 25.

A circular slicing knife 35 having a sharp outer peripheral cutting edge 36, is mounted on the upper end portion 31 of the shaft 28 and is secured to a plastic sealing ring 38 which is threaded on the shaft portion 31 and has a circumferential lip which engages an annular curved surface 39 on the upper end of the housing portion 16 to form a rotary seal between the knife 35 and the housing portion 16. A formed sheet metal knife guard 45 covers a substantial portion of the knife 35 and is mounted on the'upper end portion of a support rod 46 which extends through the tubular shaft 28. A V-shaped notch 48 is formed within the lower end portion of the support rod 46 and is engaged by the inner pointed tip of a rotatable lock pin 51 extending from a knob 52.

As shown in FIGS. 3 and 4, the lock pin 51 is threaded into a sleeve 54 which carries an inwardly projecting pin 56 (FIG. 4) adapted to actuate a normally open interlock switch 58 when the sleeve 54 moves inwardly on the lock pin 51. A compression spring 59 is mounted on the lock pin 51 and urges the sleeve 54 against an annular shoulder or surface 61 surrounding the lock pin 51. When the lock pin 51 is retracted or unthreaded, the knife guard 45 and its supporting rod 46 may be removed to facilitate cleaning of the guard and the knife 35. While the rod 46 is removed, if the knob 52 is rotated, the lock pin 51 threads itself into the sleeve 54 until the knob bottoms on the housing. The sleeve 54 remains adjacent the shoulder 61 so that the pin 56 holds the normally closed switch 58 in an open position.

When the knife guard 45 and supporting rod 46 are reassembled to the position shown in FIG. 3, and the knob 52 is rotated, the lock pin 51 threads downwardly within the sleeve 54 until the pointed tip of the pin engages the notch 48 within the rod 46. After this engagement, further rotation of the knob 52 causes the sleeve 54 to move upwardly away from the shoulder 61 thereby retracting the pin 56 from the switch 58 causing the switch to return to its normally closed position. As shown in FIG. 7, the switch 58 is connected in series with the motor 25 so that the motor cannot be energized unless the switch 58 is closed.

Referring to FIGS. 1 and 2, a generally flat gage plate 65 is supported on an angle parallel with the knife 35 by a pair of parallel spaced inclined rods 66 (FIG. 2) which are slidably received within corresponding bores formed within the housing portion 18. A pin 68 projects outwardly from the rear guide rod 66 and is received within a slot formed within an end portion of a lever 70 pivotally mounted on cross pin 72. The lever 70 includes a portion which extends between adjacent flights of a worm 74 mounted on a shaft 76 rotatably supported by the housing portion 18. A knob 78 is mounted on the outer end portion of the shaft 76 adjacent the front wall of the housing 15 and provides for rotating the worm 74 to effect-pivoting of the lever 70 and corresponding sliding movement of the gage plate 65. A graduated scale 79 is formed on the knob 78 to indicate the position of the gage plate 65 within its range of movement between a zero setting where the upper surface of the gage plate 65 is flush with the upper surface of the knife 35 and an open position where the gage plate is positioned a fraction of an inch below the cutting edge of the knife 35 according to the desired thickness of the slices to be produced.

A pair of parallel spaced guide rods 84 (FIGS. 8 and extend longitudinally within the upwardly projecting hollow portion 18 of the housing and slidably support a carriage 85 which includes a vertical hollow arm 86 mounted on a generally horizontal arm 88 slidable on the lower guide rod 84. A lever 89 is rigidly secured to the arm 88 and has a bifurcated upper end portion which receives the guide rod 84 between opposing low friction plastic studs 91.

A pair of angularly disposed surfaces 94 (FIG. 6) are formed on the upper end of the carriage arm 86 and slope downwardly parallel to the axis of the knife supporting shaft 28 on opposite sides of a slot 96. The carriage 85 includes an L-shaped tray member 100 having angularly arranged walls 102 and 103 each of which also slopes downwardly parallel to the axis of the knife shaft 28. A wedge block 105 (FIGS. 2 and 6) is secured to the underneath surface of the wall 103 and seats on the surfaces 94 on the upper end of the carriage arm 86. The wedge block 105 includes a downwardly projecting end portion 107 (FIG. 2) on which is mounted a downwardly extending tongue-like locking plate 108 having a cam slot 109. I

When the tray member is mounted on the carriage arm 86, the locking plate 108 is adapted to slide within the slot 96 below a rotatable locking pin or bolt 110 (FIG. 6) extending through the upper end portion of the carriage arm 86 and having an angularly extending handle 112. A forked or V-shaped slot 1 15 (FIG. 6) is formed within the lock-ing bolt 110 and receives the inner end of a retaining screw 116 whichenables the bolt 110 to be rotated through a predetermined angle as well as move axially within the bore which receives the bolt. A recess 118 (FIG. 2) is formed within the lockingbolt 110 for receiving the plate 108, and a pin 120 projects outwardly from the locking bolt 1 10.

A compression spring 122 urges the locking bolt 110 axially to the right as shown in FIG. 6. After the tray member 100 is seated on surfaces 94 of the carriage arm 86, and the plate 108 extends within the recess 118 of the locking bolt 110, the locking bolt is rotated with the aid of the handle 112 so that the bolt presses downwardly on the plate 108 to effect clamping of the tray member 100 to the carriage arm 86. When the lock bolt 110 is rotated, the pin '120 engages the cam slot 109 causing the lock bolt 1 10 to move axially within the upper end portion of the carriage arm 86, compressing the spring 122.

When the lock bolt 110 is cammed inwardly, a hole 123 formed within the lock pin 110 is aligned to receive the upper end portion of a locking rod 124 (FIG. 2)

which is urged upwardly within the carriage arm 86 by a compression spring 125. The lower end of the locking rod 124 is connected to the outer end of a pivot lever 126 (FIG. 5) mounted on the lower arm 88 of the carriage 85. The inner end of the pivot lever 126 is connected by a link rod 128 to a rocking plate 130 (FIG. 2) pivotally supported by a pin 132. A set of spaced tabs 134 and 136 project upwardly from the rocking plate 130 and are adapted to receive a rectangular extension portion 138 of the lever 70 which projects between the adjacent flights of the worm 74.

In normal use of the slicing machine, the tray member 100 is mounted on the upper end of the carriage arm 86, and the locking bolt 110 is rotated to its locked position where it is retained by the upper end portion of the locking rod 124 which projects into the hole 123. When it is desired to remove the tray member 110, the knob 78 is turned to its zero setting indicating that the gage plate 65 is flush with the cutting edge 36 of the knife 35. Rotation of the knob 78 causes the lever 70 to move to the position shown in FIG. 2 so that when the carriage 85 is moved to the forward limit of its stroke (FIG. 2), the inner edge of the lever 70 engages the inner tab 136 of the rocking plate 130 causing the rocking plate to pivot.

The pivoting of the rocking plate 130 moves the inner link rod 128 upwardly and the outer locking rod 124 downwardly to retract the upper end portion of the locking rod from the hole 123 within the locking bolt 1 10. This enables the locking bolt 110 to be rotated approximately l l0 for releasing the plate 108 projecting from the mounting block 105 of the tray member. When the rocking plate 130 pivots in response to engagement between the lever portion 138 and the tab 136, the forward tab 134 moves upwardly to engage the forward end of the lever portion 138. As a result, when the locking rod 124 is retracted from the locking bolt 110, the rocking plate 130 prevents rotation of the worm 74 and the knob 78 so that the gage plate must remain at its zero setting and the carriage must remain at the forward limit of its stroke as long as the tray member 100 is removed.

If the locking bolt 110 is rotated while the carriage tray 100 is removed, the locking bolt 110 will not move axially since there is no cam surface for the pin 120 to engage. Thus the hole 123 does not move into alignment with the locking rod 124, thereby preventing pivoting of the rocking plate 130 or rotation of the knob 78. As shown in FIGS. 1 and 2, the tray member 100 includes a curved guard plate 140 which projects upwardly from the forward wall 102 to help cover the knife 35 when the carriage is moved rearwardly. The tray member also supports a gripper 142 which is mounted on an arm 143 slidably supported by a guide rod 144. The gripper 142 carries a clear plastic shield Referring to FIGS. 7 and 11, a main control switch 146 is located within the base of the housing 15 and is connected in series with the motor which is adapted to receive power from supply lines L and L The switch 146 includes a toggle actuator 147 which is positioned between a pair of spaced collars 148 mounted on the inner end portion of an actuating rod 150. extending longitudinally within the base portion of the housing 115. A knob 152 is secured to the outer end portion of the actuating rod 150 and is located outboard of the front wall of the housing 15 as shown in FIGS. 1 and 2.

A collar 154 is slidably mounted on the rod 150 and is urged against the toggle actuator 147 of the switch 146 by a compression spring 155. A normally open switch 158 is positioned adjacent the main control switch 145 and is connected in series with the switch 58 and the motor 25 as shown in FIG. 7. A relay coil 160 is connected in parallel with the motor 25 and includes normally open contacts 162 which are connected in parallel with the switch 158.

When it is desired to start the motor 25 of the slicing machine, the knob 152 is pulled outwardly to effect closing of the switch 146. Continued pulling of the knob 152 causes the spring 155 to compress and the forward collar 148 to actuate the switch 158. Momentary closing of the switch 158 is effective to energize the relay coil 160 which closes the contacts 162 thereby holding the circuit closed so that the motor 25 remains energized. When the knob 152 is released, the actuating rod 150 returns to its normal position due to the force of the compression spring 155, and the switch 158 opens.

The function of the electrical control circuit shown in FIG. 7 is to assure that the motor 25 will not be energized while the knife guard 45 is being replaced and switch 58 is closed in response to tightening of the knob 52. That is, if the start control knob 152 is inadvertently pulled outwardly while the knife guard 45 is removed during cleaning, switch 146 will close. However, when the knife guard 45 is being remounted on the slicing machine, the motor 25 will not be energized when the switch 58 closes since the switch 158 and the locking the carriage tray member 100, cooperates with the gage plate actuating lever to provide an interlock system which prevents removing of the carriage tray member 100 until the gage plate 65 is set at zero and the carriage is moved to the forward limit of its stroke. Furthermore, as long as the tray member is removed from the carriage support arm 86, the interlock mechanism prevents rotation'of the knob 78 and corresponding movement of the gage plate 65 and also prevents movement of the carriage 85. As a result, at all times while the tray member 100 is removed from the carriage support arm 86, the forward exposed portion of the cutting edge 36 of the knife 35 is guarded by the rearward portion of the gage plate 65. Thus if the hand of the operator accidentally slips while he is cleaning the slicing machine, the chances of the operators hand engaging the exposed portion of the cutting edge 36 are substantially reduced.

Another important feature provided by the slicing machine of the invention is the interlock system described in reference to the mechanism shown in FIG. 3. That is, when the knife guard 45 is removed from the machine to facilitate cleaning of the knife 35, the switch 58 opens and remains open so that the motor 25 cannot be energized. Closing of the switch 58 can only be accomplished by inserting the knife guard support rod 46 into the tubular knife support shaft 28 as shown in FIG. 3, and then rotating the knob 52 until the pin 51 locks thesupport rod 46 in position after which the switch 58 is actuated by the upward movement of the sleeve 54 and the pin 56. As mentioned above, a third interlock system is provided by the electrical control circuit shown in FIG. 7 which assures that the motor 25 cannot be energized unless the start control rod or button 152 is intentionally pulled out against the bias of the compression spring 155.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that'changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In a slicing machine including a base supporting a carriage for reciprocating movement adjacent a rotatable slicing knife driven by a motor, a gage plate suping means for said tray member with adjusting means for said gage plate.

3. A slicing machine as defined in claim 2 wherein said interlock mechanism is operable only when said carriage is positioned at one end of its stroke of reciprocating movement.

4. A slicing machine as defined in claim 1 wherein said interlock mechanism is effective to prevent adjustment of said gage plate when said tray member is removed.

5. A slicing machine as defined in claim 1 including a removable guard member disposed in a covering position adjacent at least a part of said knife, and a second interlock mechanism operable to permit energizing of said motor only when said guard member is located in said covering position.

6. A slicing machine as defined in claim 4 wherein said knife is supported by a tubular shaft, said guard member is supported by a rod extending into said shaft, means for locking said rod within said shaft, a switch connected to control said motor, and means for actuating said switch in response to actuation of said locking means only when said rod is secured correctly within said shaft.

7. A slicing machine as defined in claim 4 including a main control switch for said motor, and a third interlock mechanism effective to prevent operation of said motor when said guard member is being reassembled after said main control switch is inadvertently actuated to a position for energizing said motor. 

1. In a slicing machine including a base supporting a carriage for reciprocating movement adjacent a rotatable slicing knife driven by a motor, a gage plate supported for adjustment relative to said carriage and the cutting edge of said knife, and said carriage including a removable tray member for supporting articles to be sliced, the improvement comprising an interlock mechanism operable to permit removal of said tray member only when said gage plate is locked in a position substantially flush with said knife and protecting the cutting edge of said knife.
 2. A slicing machine as defined in claim 1 wherein said interlock mechanism effectively connects retaining means for said tray member with adjusting means for said gage plate.
 3. A slicing machine as defined in claim 2 wherein said interlock mechanism is operable only when said carriage is positioned at one end of its stroke of reciprocating movement.
 4. A slicing machine as defined in claim 1 wherein said interlock mechanism is effective to prevent adjustment of said gage plate when said tray member is removed.
 5. A slicing machine as defined in claim 1 including a removable guard member disposed in a covering position adjacent at least a part of said knife, and a second interlock mechanism operable to permit energizing of said motor only when said guard member is located in said covering position.
 6. A slicing machine as defined in claim 4 wherein said knife is supported by a tubular shaft, said guard member is supported by a rod extending into said shaft, means for locking said rod within said shaft, a switch connected to control said motor, and means for actuating said switch in response to actuation of said locking means only when said rod is secured correctly within said shaft.
 7. A slicing machine as defined in claim 4 including a main control switch for said motor, and a third interlock mechanism effective to prevent operation of said motor when said guard member is being reassembled after said main control switch is inadvertently actuated to a position for energizing said motor. 